The present invention relates to improvements in machines for the production and/or processing of cigarettes and/or other types of rod-shaped articles which constitute or form part of smokers'products. More particularly, the invention relates to improvements in the making of rod-shaped articles which are produced by drawing a relatively thin but wide continuous layer of tobacco particles from a suitable source, converting the layer into a narrow continuous stream which moves lengthwise, draping the stream into a web of cigarette paper or the like to form a wrapped stream or rod, and severing the rod at selected intervals so that the rod yields a succession of rod-shaped sections (e.g., plain cigarettes) of unit length or multiple unit length. The above-enumerated steps can be carried out in a cigarette maker or another machine wherein a distributor contains a supply of tobacco particles and is provided with means for forming the layer, for converting the layer into a narrow stream, for trimming the stream, for draping the trimmed stream (filler), and for converting the resulting rod into discrete rod-shaped articles. As a rule, the stream and the filler are attracted by suction to one or more foraminous belt conveyors so that they remain in the prescribed path and advance at the speed of such conveyor or conveyors.
It is already known to monitor the operation of a cigarette maker or another machine or combination of two or more cooperating machines which produces or processes rod-shaped articles constituting or forming part of smokers' products. Such monitoring is desirable and advantageous because rapid detection of a malfunction can greatly reduce the losses in output; this is particularly important in modern high-speed cigarette makers or like machines which turn out in excess of 100 articles per second. Thus, it is desirable to ensure that the down times of the machine be reduced to a minimum because each and every minute of stoppage entails the loss of more than 6000 articles. As a rule, a cigarette maker, a filter tipping machine, a filter rod maker, a packing machine or an analogous machine which produces or processes rod-shaped articles of the tobacco processing industry is equipped with a host of monitoring devices which are designed to ascertain numerous widely different causes of malfunction. In most instances, the detection of a defect or malfunction entails immediate stoppage of the entire machine, group of machines or production line. One of the numerous malfunctions or defects is the breakage of the cigarette rod in a cigarette maker (such defect or malfunction is also known as a stopper). The primary or frequent cause of such types of defects is a pileup of tobacco particles at the inlet of the mechanism which drapes a continuous web of cigarette paper or other suitable wrapping material around a rod-like filler of tobacco particles, i.e., around a stream which has been trimmed or equalized for the purpose of removing the surplus of tobacco therefrom. The accumulated particles are incapable of advancing beyond the inlet so that the filler breaks downstream of the inlet to thus cause a breakage of the web of wrapping material. This means that the customary cutoff is incapable of subdividing the cigarette rod into rod-shaped articles of desired length, and the absence of articles is detected by a suitable monitoring device to initiate stoppage of the cigarette maker. Such monitoring device is normally installed at or close to the discharge end of the cutoff, i.e., not far from the inlet of the draping mechanism. Nevertheless, the relatively short interval of time which elapses between the instant of breakage of the rod and the detection of absence of rod-shaped articles at the discharge end of the cutoff suffices to entail complete or substantial clogging of the path along which the tobacco stream advances from the stream forming zone to the inlet of the draping mechanism. This holds especially true for the aforediscussed modern cigarette makers which turn out extremely large quantities of rod-shaped articles per unit of time. Accumulations of tobacco particles upstream of the inlet to the draping mechanism entail clogging of a portion of the distributor as well as of the channel wherein the untrimmed stream and the filler advance toward the draping mechanism. Consequently, each breakage of the cigarette rod necessitates an opening of the distributor, removal of accumulated tobacco particles, cleaning of the channel wherein the stream advances toward the draping mechanism, and cleaning of the conveyor means which transport the stream and the filler toward such mechanism. As a rule, the cleaning operation is performed by hand which is a time-consuming operation and can take up an interval of time during which the machine would have turned out tens and tens of thousands of smokers' products. Moreover, the machine must be provided with numerous doors and/or openings which afford access to certain portions of the distributor and to the tobacco channel. Still further, tobacco particles which pile up in the distributor and/or in the tobacco channel are highly likely to be comminuted so that they must be discarded or subjected to costly treatment preparatory to readmission into the distributor of the cigarette maker. Finally, breakage of the web of wrapping material necessitates the initiation of a splicing operation which also involves losses in time and often requires attendance by a skilled operator.